This invention relates generally to a circuit board assembly for an electronic timepiece and more particularly, to a circuit board assembly having a plurality of compartments for individually housing electronic components such as an oscillator, an IC chip, etc.
In the conventional type circuit board assembly for an electronic timepiece, as shown in FIG. 1, the circuit board 10 contains a printed pattern of electrodes 2 on one or both sides thereof, a terminal pin 3 for connection to a switch, and a set of openings or recesses 10A for housing an IC package 8 and a trimmer capacitor 4. An oscillator unit 7 is mounted on the circuit board 1 and connected by pins 5 to the electrodes 2. By such a construction, the electronic components, such as the IC package 8, trimming capacitor 4 and oscillator unit 7, are fixed to the circuit board 10 by separate connecting steps thereby making it difficult to simplify the assembly of the various electronic circuits. Furthermore, since the thickness of the circuit board is increased due to the mounting of the components on the sides thereof, it is difficult to employ such a circuit board to make a thin electronic watch.
FIG. 2 shows another prior art type circuit board assembly for an electronic timepiece. In this construction, an oscillator 21 and an IC chip 22 are closely housed or packaged in the same compartment 23 and though this results in a small size construction, it is difficult to wirebond the oscillator 21 and the IC chip 22. In addition, this type construction is relatively fragile and hence the components are apt to break if a mechanical shock is imparted to the watch. Moreover, it is inconvenient to carry in stock a supply of circuit boards in the incomplete or partly assembled state, such as shown in FIG. 3, because the IC chip 22 is apt to be damaged if it is touched by mistake, and will deteriorate by being exposed to the open air.
Another conventional type circuit board assembly is shown in FIG. 4. In this modification, the oscillating frequency of an oscillator in the form of a quartz crystal vibrator 24 is adjusted to a predetermined resonant frequency in a known manner by applying thereto a laser beam through the transparent portion 25 of a case 26. An IC chip 27 is mounted with the vibrator 24 in the same compartment and therefore the IC chip is apt to be damaged by the laser beam during the adjustment of the vibrator resonant frequency.